ABSTRACT
At the beginning of a moult a foam secretion appears between the epidermal cell surface and the old cuticle. This secretion is involved only with the lifting away of the old cuticle and formation of the exuvial space. A granular secretion then appears in the exuvial space. The granules contain inactive moulting enzymes, which become active only after the completion of the new cuticulin layer, and then digest the soft parts of the old cuticle. The rest of the new cuticle is laid down extracellularly and in lamellae below the cuticulin layer. The sculpturing of the new cuticle occurs under the influence of the epidermal cells. Subsequent hardening of certain areas of the new cuticle involves disruption of the lamellae and complete reorganization. Setae are formed early and rapidly, but nervous connexions with the old setae are maintained until just before ecdysis. Muscle insertions into the new cuticle are formed early, but attachment to the old cuticle is retained until ecdysis. The cuticulin layer is involved in the formation of the new attachments.
